High integration of semiconductor devices plays a significant role in the development of electronic media that necessitate large data storage capacity and high data processing speed. The importance of miniaturization of semiconductor devices is also emphasized by the advancement of multi-functional mobile electronic media. The requirements for high integration and miniaturization make planarization processes important in achieving smaller linewidths in the manufacture of semiconductor devices.
Chemical mechanical polishing (CMP) processes have been employed to manufacture semiconductor devices having small linewidths. Generally, polishing slurries for use in CMP processes include deionized water, abrasive particles, and optionally, a polishing performance assistant or a stabilizer. Such CMP processes are based on the principle that a polishing slurry is supplied in a state where a material to be polished is placed in contact with the surface of a polishing pad such that the polishing slurry is chemically reacted with the surface of the material and at the same time the polishing pad is moved relative to the material to physically planarize irregularities of the material.
CMP processes for the formation of semiconductor interlayer dielectrics (ILDs) are carried out to polish convex surfaces of a single-layer material having a step height at a higher rate than the polishing rate for concave surfaces acting as polishing stop layers of the single-layer material, thereby planarizing the single-layer material. Generally, slurries for ILD polishing have a slight difference in polishing rate between concave surfaces and convex surfaces of semiconductors, which makes self-stopping of the polishing process difficult. In addition, generally slurries suffer from many problems in terms of surface characteristics and storage stability.
As mentioned above, as semiconductor devices become more densely integrated and smaller in size, CMP processes will be of increasing importance. However, many improvements, such as high planarity and reduction of defects, are still required to manufacture devices with ultrafine linewidths.